How much sleep do our bodies need?
| You hear it all the time: in order to function like normal human beings, we’re always being told we need to get eight hours of sleep, every night of the week. But what are the consequences if we don’t get that much? Will our bodies start falling apart? |
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The advent of electricity has brought about a fundamental change in the way humans live — there are reasons now to stay awake.A Adelaide sleep researcher Nicole Lamond, from the University of South Australia, is a leading researcher in the field of sleep deprivation. She says our reduced reliance on sleep is problematic: “We suffer both emotionally and physically if we don’t get sleep.”Therefore this theory is put to the test: five university students will check into Nicole’s sleep lab for a night of fun and frivolity. |
| Lauren: | Will sleep for eight hours. |
| Phoebe: | Will sleep for six. |
| Emma: | Four hours. |
| Alexandra: | Two hours. |
| Melissa: | Won’t get any sleep at all. |
| The girls will be run through a few performance tasks before heading to bed. A driving simulator will test the girl’s ability to concentrate, while a response time task will test their reaction times in milliseconds.The girls will again be tested the following morning to see how they go on the same tasks. The outcomes will therefore help determine how much, or how little sleep our bodies really need.The test gets underway at 11pm as Lauren is put to bed for her eight-hour beauty kip. The rest of the girls are taken out for some fun, games and pool at an Adelaide nightclub. They aren’t allowed any stimulants — so, no caffeine or alcohol.At 1am, Phoebe hops into bed back at the lab where she’s got six hours of dreamtime ahead of her. |
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By 3am the nightclub is closing and it’s bedtime for four-hour girl Emma. Two hours later Alexandra tucks in for her two-hour kip while Melissa, who gets zero sleep, rapidly loses her kick without any of her friends left around — she’s longing to curl up between the sheets like the other girls.Nicole says that the way human sleep works is that it is divided into five different stages: |
| Stage one: | This is known as non-Rapid Eye Movement (non-REM) sleep — where we’re half awake and half asleep and can awaken easily at this stage. Muscle activity slows down and slight twitching may occur. |
| Stage two: | Within 10 minutes of light sleep (stage one) we enter True Sleep — the period we spend most of our night in. |
| Stages three and four: | By the time we begin Deep Sleep our body has begun restoring itself to function normally the next day. |
| Stage five: | Rapid Eye Movement Sleep (REM sleep). This is when the brain is at its most active and when dreams occur. REM usually begins about 70 to 90 minutes after falling asleep. We have around three to five REM episodes a night. After REM sleep, the whole cycle begins again. |
| So basically we cycle through these stages through the night. There’re about 90 minutes to 120 minutes each cycle and we sort of have four or five cycles during the night, says Nicole. |
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| The sleep lab girls rise at 7am to see how they go again on the driving simulator and the reaction time test. This will determine how much sleep (or lack of it) affects you. |
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| Melissa: | Her average reaction time after a sleepness night — 60 percent slower than the day before. |
| Emma: | After only four hours sleep, Emma is reacting 15 percent slower. |
| Phoebe: | Is four percent slower after a six-hour sleep. |
| Lauren: | Shows no change after sleeping for eight hours. |
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Yes, it is true — we do need around eight hours of sleep a night to perform optimally. If you can only manage six, your ability to function normally will only be slightly impaired, so long as this is a one-off occasion. Once you go below six hours on a regular basis, that’s when problems start occurring. So whatever you do, don’t take after the zero- and two-hour sleepers Melissa and Alexandra. According to Nicole, your reaction time and decision making when you’ve been awake for a whole 24 hours is just as bad, if not worse, than if you’ve been at the pub and drank 10 beers.If on one night you only have a four-hour sleep, then the key thing is to try and get at least nine hours the following night to recover. But you also don’t want to oversleep as you may find it difficult to get off to sleep the following night.”If you could at least get seven hours or more that would be fantastic and you’re unlikely to see any daytime effects or impairment,” says Nicole. |
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Ty Tran on February 10th 2008 in Interesting